The present invention relates generally to the fields of pisciculture and aquatic resource management. More specifically, the present invention relates to an apparatus and method for immobilizing a non-anesthetized fish of a known and fixed orientation.
Pisciculture is the breeding, hatching, and rearing of fish under controlled conditions, in either fresh or salt-water environments, as a science or industry. Aquatic resource management involves the management of natural fish populations, as well as the management of governmental fish hatcheries where fish are raised for eventual release into the wild.
In both fields, it is often necessary to perform routine fish handling operations on a large number of live fish. Examples of these operations include sorting fish by size, electronic counting, automated vaccinations, and fish tagging/marking.
One method of marking fish is to remove the adipose fin of the fish to indicate the particular origin of the fish. For example, known fish hatcheries remove the adipose fin of hatchery-born fish by hand to distinguish the hatchery-born fish from native fish. To remove the adipose fin by hand, the fish must be anesthetized, picked up by hand, have its adipose fin cut, for example, by scissors, and then revived. To perform any additional marking, such as inserting tags, the fish must be further again anesthetized before the additional marking.
This type of marking by hand, however, suffers from several shortcomings. First, the number of fish that can be marked by hand is limited. For example, twelve people removing the adipose fin of fish by hand can process approximately only 40,000 fish during an eight hour shift. Second, repeatedly anesthetizing the fish is unhealthy for the fish and can result in numerous fish deaths. Third, the natural habitat of the fish can be unfriendly for the persons performing the marking by hand. For example, where the natural habitat of the fish is very cold water, this cold water can be very uncomfortable to the persons performing the marking by hand over the period of several hours.
It would be desirable to automate operations such sorting fish by size, electronic counting, automated vaccinations, and fish tagging/marking. One problem in automating such operations is that the fish of a known orientation need to be held so that the appropriate operations can be performed on a repeated and high volume basis.